What's wrong with me that the whole world thinks that Christmas song of hers is so great, and it doesn't do a thing for me at all. 
Nothing's wrong with you. Just means that you may prefer classics or more traditional sounding Christmas music.
I think that Mariah's song is so popular because it's the "newest" Christmas song to top the Hot 100.
The way that music is streamed and downloaded now influences the Hot 100 chart, and each Christmas we see many Christmas songs hitting the Hot 100 each year, and Mariah's song always slams into the #1 spot each year. The rest of the Top 10 tends to be classics.
This week's Top 10 has these songs in it (release years in parenthesis):
#1 - All I Want For Christmas Is You - Mariah Carey (1994)
#2 - Jingle Bell Rock - Bobby Helms (1957)
#3 - Rockin' Around The Christmas Tree - Brenda Lee (1958)
#4 - Last Christmas - Wham! (1984)
#6 - The Christmas Song (Merry Christmas To You) - Nat "King" Cole (1958)
#8 - Let It Snow! Let It Snow! Let It Snow - Dean Martin (1959)
#9 - The Most Wonderful Time Of The Year - Andy Williams (1963)
You'll note I skipped #s 5, 7, and 10. #10 is not a Christmas song, it's "Ophelia" by Taylor Swift, the only non-holiday song in the Top Ten this week.
The two remaining songs are holiday hits, and they were both recorded in the past 12 years, and it's the first time since Mariah's song in 1994 that new Christmas music has hit the Top 10.
#5 - Santa Tell Me - Ariana Grande (2014)
#7 - Underneath The Tree - Kelly Clarkson (2013)
If you are unfamiliar with these two new songs, here are the videos for them.